Passing large amounts of data between actors without making copies

Using Swift
40

Unfortunately, actors are not a silver bullet for resolving high-level data races either :-(

In a way they could give "an illusion of correctness" because they eliminated all low-level data races (the presence of which (e.g. in a form of runtime traps) would otherwise bring developer's attention to potential issues).

Illustrating example 
// Edit: simplified a bit

actor State {
    private var state = 0
    func get() async -> Int {
        await someLogStatement()
        return state
    }
    func set(_ newValue: Int) async {
        await someLogStatement()
        state = newValue
    }
}

let state = State()

Task {
    // data race
    await state.set(state.get() + 1)
}
Task {
    // data race
    await state.set(state.get() + 1)
}
Task {
    try await Task.sleep(nanoseconds: 100_000_000)
    let result = await state.get()
    print("resulting value is \(result)")
}

func someLogStatement() async {
    try! await Task.sleep(nanoseconds: .random(in: 0 ..< 1000_000))
}

RunLoop.main.run(until: .distantFuture)

Concurrency is hard.